This invention is concerned generally with crop roll forming machines. Specifically, it is addressed to an improved tensioning apparatus for the bale forming means of a crop roll forming machine that is easily adjustable and permits variable tension to be applied to the bale forming means under appropriate crop conditions from the time a bale is initially formed until it is a completed crop material package.
Historically, it has been the custom to harvest forage crops by mowing the crops, letting them dry in the field, forming the dried crop material into windrows and passing a hay-baling machine over and along those windrows to form the crop material into rectangular bales. This technique suffers from the disadvantage, however, of having to gather the rectangular bales from the field and transport them to a storage area protected from the elements since rectangular bales exposed to precipitation will retain sufficient moisture to rapidly spoil and consequently be useless for forage purposes.
A former practice utilized a hay-baling machine that gathered the dried, precut crop material from the field and formed it into small diameter cylindrical bales. Although this practice produced a crop material package that had a shaped surface that would tend to shed the moisture produced by inclement weather, it suffered from the same basic disadvantage as the rectangular baling procedure since spoilage occurs to the outer layer of the crop roll. Since the depth of spoilage of the outer layer in relation to the overall diameter of these small crop rolls was relatively great, it was not economically practical to expose these small diameter rolls to the weathering process. Therefore, these rolls also had to be removed from the field to a protected storage area.
Recent practice has shown that the formation of crop materials into large compact rolls, rather than rectangular bales or small rolls as formerly done, permits the crop material to be deposited in roll form and left in fields for extended periods of time since the rolled material tends to provide a self-shredding protective covering from inclement weather. The depth of what spoilage that does occur in relation to the overall diameter of such a roll is minimal and, therefore, storage in exposed areas is practical. The ability to leave these rolled bales in fields thus obviates the additional steps of gathering the rectangular bales or small diameter crop rolls and transporting them to a storage area protected from the elements. The practice of forming large round bales of crop forage material has become increasingly popular since it is labor extensive and has proven to be a commercially feasible and lucrative practice for relatively small scale farms, as well as large custom hay operations.
This increasing popularity of large crop roll forming machines has been manifested in their broadened use from rolling wintering forage for livestock to rolling high protein crops, such as alfalfa, for dairy livestock. Concomitantly, these large crop roll forming machines have been used in a wider range of crop materials and under a wider range of crop conditions.
There are generally two principal types of large crop roll forming machines on the market today. These types are determined by the nature of the bale forming means utilized. This apparatus employs either a series of endless belts or a combination of chains and slats of some type to encompass the crop material. The bale forming means generally determines the density of the forming crop roll by expanding with the bale under predetermined amounts of tension while additional crop material is wrapped about the bale. Examples of these types of machines embodying these different bale forming means are shown in U.S. Pat. No. 3,722,197 dated Mar. 27, 1973, and in U.S. Pat. No. 3,859,909 to Mast dated Jan. 14, 1975.
Machines of the type just described have been continually faced with dual, and sometimes antithetical, areas of concern by having to offer good core formation characteristics and still produce bales of relatively high density. A large round bale's density primarily is a function of the amount of tension that is applied to the bale forming means which causes compressive forces to be applied to the bale along the surface of contact of the bale forming means therewith. During the initial stage of the bale forming process the center of the roll bale, or core, is formed. Excessive compressive forces caused by too much tension being applied to the bale forming means can cause the core to breakup. This is especially true in short, brittle and dry crops such as straw, maize butts or corn stover, where the crops will merely crumble under excessive pressure as the core grows and engages the resistive mold of the bale forming means. The fact that different crops require different core formation compressive forces to initiate the roll forming process makes difficult the manufacture of a single large crop roll forming machine for all crops and all the different types of crop conditions that can be encountered. Indeed, many commercial balers today consistently can form round bales in only a portion of the crops used for forage because of this. Additionally, after the core is formed the need to satisfy the demand for higher density bales presents the contrasting problem of having to apply an increasingly greater tension force to the bale forming means. Therefore, the need for a machine that will operate in a wide range of crops under a broad spectrum of crop conditions requires an easily adjustable tensioning apparatus for a bale forming means in a large crop roll forming machine that can be tailored to the specific crop conditions in the particular crop being rolled during core formation, as well as provide a generally increasing tension on the bale forming means during the remainder of the bale forming process.
The foregoing problems are solved in the design of the machine comprising the present invention by utilizing an improved tensioning apparatus for the bale forming means of a crop roll forming machine that is easily adjustable to permit the required appropriate level of tension to be applied to the bale forming means initially to form the core of a large round bale for each particular crop material being rolled, as well as providing the generally increasing tension needed to form crop material packages of the desired density.